This film, produced in the Lawrence Radiation Laboratory of the University of California, Berkeley, features four scientists who were principals in the discovery and identification of several of the transuranium elements. Glenn Seaborg reviews the historical problem of the placement of the transuranium elements in the periodic table. Burris Cunningham performs experiments showing that neptunium, plutonium, and americium have chemical properties similar to those of uranium, but that under the same experimental conditions curium behaves like its rare-earth homolog, gadolinium. Stanley Thompson demonstrates how the ion-exchange separation technique is used in identification, using actual solutions of curium, berkelium, californium and einsteinium. Albert Ghiorso discusses the methods used in the synthesis of elements 102 and 103, and proposes a similar type of reaction which may lead to the discovery of element 104.